Katorazone, a new yellow pigment with a 2-azaquinone-phenylhydrazone structure produced by Streptomyces sp. IFM 11299

An unusual alkaloid with a 2-azaquinone-phenylhydrazone structure, katorazone (1), and other metabolites were isolated from the ethyl acetate extract of Streptomyces sp. IFM 11299. The chemical structure of katorazone (1) was elucidated by 1D and 2D NMR analyses together with HR-ESI mass spectrometry. Katorazone (1) showed a synergistic effect in combination with TRAIL and decreased the viability of human gastric adenocarcinoma (AGS) cells.